The present invention is directed to a holding mechanism for mounting a measuring cryostat which is used to acquire biomagnetic signals.
Since the measuring cryostat comprises a magnetic measuring coil and the movement of this coil in the micrometer range is undesirable, high demands are made on the stability of a holding mechanism for the cryostat. At the same time, the greatest possible flexibility with respect to the manipulatability and adjustability of the measuring cryostat having the coil should be established.
Included in these demands is an easy height adjustability for different measuring positions given a patient who is either lying or sitting, and also a height adjustment for working with the cryostat, such as when replenishing the liquid helium therein. Also included in these requirements is the simple maneuverability of the measuring cryostat on a spherical surface, whose center lies within either the head or the thorax of the patient being tested or measured. The radius of the spherical surface to be traversed should, therefore, be adjustable insofar as possible. In addition, the measuring coil should be capable of being adjusted relative to the interesting measurement region of the head or thorax of the patient and be also adjustable by rotating the measuring element relative to the cryostat axis.
Another desirable condition, which should also be met, is that the holding mechanism is as free as possible of any mechanical resonance. Finally, the mechanism should also provide access to the patient and to the cryostat for the purpose of maintenance work. In addition, the safety standards for the protection of the patient which is standard in medical technology must be observed and achieved.
A measuring cryostat of the type under consideration in the present invention for the measurement of biomagnetic signals is known. An example is disclosed by an article by D. Crum "The Design and Use of Dewars for Biomagnetic Measurements", Biomagnetism: Application and Theory, edited by H. Weinberg et al, Pergamon Press, New York, 1985, pp. 21-34.